Apparatus for heat-treating gun



April 7, 1942. H. E. SOMES Re. 22,064

APPARATUS FOR HEAT TREATING GUN BORES Original Filed Jan. 21, 1937 5Sheets-Sheet l INVENTOR.

HQWARDE. S OM25.

97 L/-Qb j ATTORNEY.

April 7, 1942. H. E. SOMES APPARATUS FOR HEAT TREATING GUN BORESOriginal Filed Jan. 21, 19:5

'T 5 Sheets-Sheet 2 b6 INVENT OR. 5 HOWARDESOMES ATTORNEY.

April 7, 1942. H. E. SOMES I Re. 22,064

APPARATUS FOR HEAT TREATING GUN BORES Original Fil ed Jan. 21, 193'? 5Sheets-Sheet 5 Vi V I i'e'mm' air-Kwanzaa -95 f '4 v w I A2 I nINVENTOR.

H OWARDE.SOME$.

ATTORNEY.

5 Sheets-Sheet 4 i4. E. SCDBAEES APPARATUS FOR HEAT TREATING GUN BORESOriginal Filed Jan. 21, 1937.

April 7, 1942.

mvsmom Howmnijorms.

ATTORNEY.

' April 7, 1-942. H. E. SOMES APPARATUS FOR HEAT TREATING GUN BORESOriginal Filed Jan. 21, 1937 5 Sheets-Sheet 5 INVENTOR, HOWARD E. S ONESv ATTORNEY.

Reissuecl Apr. 7, 1942 APPARATUS FOR HEAT-TREATING G BORES Howard E.Somes, Grosse Pointe Park, Mich., assignor to Build Induction Heating,Inc., Philadelphia, Pa., a corporation of Michigan Original No.2,208,607, dated July 23, 1940, Serial No. 121,598, January 21, 1937.

Application for reissue July 22, 1941,

7, 1939. Serial No. 403,590

23 Claims.

The title of this invention indicates the class to which it belongs. Thefigures of the drawings following show one embodiment of my invention.As usual it is susceptible of many others.

Fig. 1 is a vertical side elevation of the apparatus.

Fig. 2 is a front elevation at right angles to Fig. 1.

Fig. 3 is a transverse cross section of the vertical framework of theapparatus.

Fig. 4 is a plan view of the lower bracket arm.

Fig. 5 is a plan view of-the end of the support ing arm.

Fig. 6 is a plan view at the top of the base block supporting the work.i i

Fig. '1 is a side view in vertical axial section of that portion of theapparatus lying within the rectangle 1 of Fig. 1, showing the switchingtransformer and tool carriage on an enlarged scale.

Fig. 8 is a fragmentary enlarged view of the upper end of the machinelying within the dotted rectangle 8 of Fig. 1, portions of the samebeing shown in vertical section.

Fig. 9 is a fragmentary enlarged view of the lower end of the machinelying within the dotted rectangle 9 of Fig. 1,- portions of the samebeing shown in vertical section.

Fig. 10 is a transverse section of the quenching mechanism feed on line5-5 of Fig. 1.

Fig. 11 is a detail of the quenching spray head.

Fig. 12 is a longitudinal sectional view of a gun treated in accordancewith the invention.

Fig. 13 is a circuit diagram of the control system.

The central object of the invention is the achievement of an apparatuswhereby the bore of a gun can be heat treated by high frequencyinduction. Sofar as I am aware this has never been achieved prior to myinvention.

According to my invention there is generated in one axial region of thebore annular heating currents in and near the surface of the bore and ofa determinate axial extent, progressively shift the currents sogenerated axially of the bore to circulate through successive axialportions of the bore, and as the currents are so shifted. quench theheat which has been generated by the currents so circulated and shifted.Preferably I uniformly progressthe axially shifting Renewed April tomaintain between the zone traversed by the progressing induced currentand the zone being quenched a zone which has been heated to quenchingtemperature by the axial shifted current but momentarily i'ree fromsubstantial influence of either the shifting current or the quench.Preferably I begin the inducing of the treating current outside of thebarrel and of an intensity and volume approximating that which shall begenerated within the barrel and similarly end the inducing of current ofsimilar intensity and volume at the opposite 'end of the gun, alsooutside of the barrel. The current, the inducing of which has so begunand so ended, is progressively shifted in the one case into one end ofthe barrel, and after being progressed throughout the extent of the boreis similarly shifted out of the opposite end thereof.

The apparatus comprises means to support the gun with free spacesubstantially equal to its length disposed axially beyond each endthereof and freely accessible from the end. In the free space at one endis'a mechanism for progressing into along, back along and again out ofthebore of the gun a high frequency induction work coil of a dimensionadapted to induce in the surface of the bore and in proper proximitythereto, the heating currents desired. Occupying the space at theopposite end of the gun is a mechanism for introducing to the boreprogressing therealong, back therealong and then out again, a.

quenching head through which quenching fluid may be projected upon theheated bore 450 be quenched. Coordinated motor driving devices for thesetwo devices, and an'into-device spacing mechanism between the highfrequency induction work coil and the quenching head insure currentswhich achieve the heating, and uniformly progress the quench of thoseheated portions from which the current has been shifted. Preferablyduring the process of shifting I maintain a. determinate axial spacedrelation between the zone traversed by the currents and the zonesubjected to the following quench so that the zone of the bore which hasbeen heated fully to quenching temperature will precede this space. Fromanother angle it may be said that I prefer their coordinated traverse ofthe bore of the gun from one end to the other in proper spaced relation.A chronometrically driven controller insures a coordinated activity ofthe various parts of these devices in their functional relations to eachother individually and collectively. A means to introduce a dry inertgas under pressure to the bore being treated and progressing it underpressure between the high frequency induction coil and the bore andcountered to the flow of the quenching medium prevents vaporized andsprayed quenching medium and other mois-, tures from engaging upon theheated surfaces of the bore and thereby attains its treatment withoutmarring its surfaces, either through oxidation, de-carbonizing orthrough electrical faults brought about by the excess presence ofmoisture.

' Referring then to the drawings, III is the gun,

I I l is the main frame of the apparatus both vertiand centered upon aflangedlcentering ring II borne upon the head of a base block llappropriately anchored as by bolts I! to the foundation of the floor. Itis retained in place against axial displacement .not' only by the flangell of the plate II, but also by an encircling clamping block I! which ismade in two halves hinged togun through the swinging link pin llengaging its pposite side in a well known manner.

The standards ll of the main frame of the machine are anchored to theconcrete floor or other platform]! in any suitable" manner andprojecting vertically upward. They support the upper end of the gun Illby means of a laterally pro- Jecting arm 20, which arm is verticallyadiust able up and down the reduced cross section II of the standard IIand clamped in any adjusted position by means of the bolts 22 whichconnect together the halves which embrace the shaft ii. The end whichengages the muzzle of the gun I is also made in twohalv'es, as indicatedat 23, the one of which is integral with the arm ll and .gether at IIand clamped together and about the upper and lower bracket respectively,to be rotated at its upper and driven carried at the end of the shaft ofthe motor mounted uponthe top of the upper bracket arm by means of abevel gear 44 secured end by means of a suitable key 45 with the toolcarriage ll through the internal threaded portion ll of the carriagethrough which it passes for elevating and lowering the carriageaccording to the direction of rotation of the other swingable about thepivot 24 to engage and center-the upper end of'thegun through theV-shaped jaws 25 and thereafter be clamped firmly thereupon by the linkpin 26 connecting together the opposite ends of'the halves from thepivot 24. Between the floor level II and this arm II supporting,aligning, centering and clamping the uppe nd o the unis located atransverse inter-column brace member. 21 for the three columns ll.Such'a brace is located also at the extreme upper end, it. will be seen.and as many of these inter-column braces may be utilized at differentpoints as it may prove expedient to use.

Each of these comprises a generally triangular main body, one apex ofwhich, 2|, is made in halves and fixedly clamped about the centralcolumn Ii and the two other aplces of which are made in halves bridgedby a common hinged bridging member 29 pivoted by a hinge 30 to the mainbody I! and coupled to the main body at the end opposite the hinge 30 bymeans of the link,

pin coupler 3|. These members 2.! engage shouldersjl respectively uponthe columns. They do not engage the barrel of the gun. Instead,

the main body is provided with an opening 33. concentric with the axisof thegun and large enough for the barrel to pass freely therethrough.If desired, however, adapters may be placed in this opening ofsuflicient size to engage the barrel and be clamped about it by thebridging member 29 when the members 21 are arranged in place.

The opening of the bracing members 21 through the swinging of thebridging member 2! enables the guns to be placed in the apparatusandrerod 52.

moved therefrom without dis-assembly of the apparatus and to berather-than raised sition.

placed, in position laterally or lowered vertically into po- On theupper portion of the main frame column H are mounted upper and lowerswing'able bracket arms ll and 35, at opposite ends of a spacing sleeve36, the upper bracket arm 34 being mounted-upon the reduced upperportion of the main frame column I I. and arranged to be carriage Mwhich it supports on a rotatable feed screw shaft ll journaled atopposite ends in the clamped in position thereon against shoulder I1shown. Mounted within the screw shaft. The bracket 49 mounted on thecarriage ll carries the heating coil supporting rod 85 and a motorcylinder 50 which movably supports the casing former.

The transformer casing Si is supported for definite limited movement bythe work cylinder Bl relative to the rod 88 by means of the tubularpiston rod 52 carried by the piston 51 fitted in the work cylinder aboutthe former casing comprising upper and lower portions lit-55 is providedin its lower portion with a cylindrical transformer primary element 5651 carrying nested within its inner cylindrical surface the primary'transformer winding 58 whose terminals 59-60 extend outwardly throughthe transformer casing for connection with a suitable source ofalternating current, not the transformer casing Si is the secondarytransformer element 62 comprised in general of the secondary'transformer winding 53 imbedded in the outer surface portion of a hollowlaminated core element St, the whole assembled between and plates ii andcarried upon the hollow vertical slide rod 66 in fixed relationtherewith so that when the piston 53 of the work cylinder 50 is moved toits lowermost position in the cylinder, the secondary transformerelement 62 will remain stationary while the transformer casing 5| willmove downwardly relative thereto. This relative movement will bri g theprimary transformer" element 56 and W1 itthe primary winding 58 downover the laminated core extension 6|, the latter providing a-lowreluctance core element for the primary winding.

The hollow rod 66 is held flxed in relation to the cylinder 5|! andbracket is at its upper end by means of the'shouldered portion 81 andthe nut 68, the transformer casing Ii having sliding bearing on the rod66 through the tubular piston The hollow rod 66 has sliding bearing inthe bushing in the bracket 3! through which bushing it extends downintoand through'the barrel of the gun III to the breech end where it carriesthe inductive heating coil II which in its present lowermost position isbreech within a lower terminal chamber H in P the base block ll.

Circuit connection between the winding 63 of the transformer secondaryelement and the heating coil 10 is effected by means of the secondaryterminals 12 and tubular conductors '73 which extend down through thehollow tube 66 to the terminals of the heating coil ll. Cooling water iscirculated through the tubular'conductors 13 for supply of coolingliquid to the transformer secondary coil and the heating coil III bymeans of the upper extensions of the tubes B which armsll and l! bymeans of suitable ball bearing journals l2 and I3 the screwshaft 4|being arranged by 'a complementary bevel gear I r The screw shaft ll isin driving engagement SI of a switching trans-v rod 66. Thetranscomprising a cylindrical laminated core element situated outsidethe spacing piston or closure element 00.

- hereinafter explained in connection with the description of operation.

Like the secondary transformer element 62 the heating coil I is {formedof a hollow conductor carried upon a cylindrical radially laminated coreelement I1, but with an outside diameter proportioned to passfreely'through the barrel of the gun out of contact therewith and inclose proximity to the surface of the bore.

At the muzzle of the gun I0 I provide an upper terminal chamber similarto the; lower terminal chamber and like the chamber 10 provided with aradially laminated lining or wall 19, so positioned and proportioned asto receive and surround the heating coil 10 when the latter is drawn upthereinto, to provide a low reluctance magnetic circuit for the coil.The chamber 10 is hermetically sealed to the muzzle of the gun I0 bymeans of the gasket element 00 fitted between the lower opening of thechamber and the muzzle of the gun, and a stuiilng box BI at the top ofthe chamber for the hollow rod 66. Pressure control valve 82 connectedwith the upper end of the ,terminal chamber 10 provides for the introduction of a dry inert gas under pressure from a suitable source notshown, whereby the chamber 10 and the gun barrel I0 may be maintainedfilled with an inert gas under pressure, the gas passing on down throughthe clearance between the heating coil I0 and the bore of the gun intothe lower terminal chamber II to an outlet conaa,oo4

extend up through the much tube above the bracket 49 as indicated at 14'where they mayand vertically sliding rack element 93 carrying bracket 90to which the lower end of the tube.

06 is fixed. The driving motor is adapted to exert suflicient lift onthe tube 00 to cause it to follow the heating head upwardly through thegun barrel and without undue upward pressure on the heating coil. Astationary brace and guide element for the rack 93 extends vertically'be tween the floor support I! and a lower stationary duit 03 whichlatter provides an outlet permitting complete displacement of air orother undesirable substance from the gun bore by the inert gas.

A lower extension 00 of'the bottom terminal chamber II extends downthrough the supporting floor I! into communication with a quenchingfluid exhaust chamber 05. Through this chamber a sliding quench-tube 80passes up 'into the lower extension 80 of the lower terminal where thetube carries a quenching head 01 spaced from and substantially sealedoil from the heating coil 10 bymeans of a piston head 00 and centerprojection BSfitting into the open end of the hollow core of the heatingcoil 10. The tubular rod 06 enters the exhaust chamber 05 throughsuitable stuffing box 90 and is mountedfor vertical movement to progressthe quenching head 01 up through the lower terminal chamber II into andthrough the bore of the gun to the upper or muzzle end of the gun, andto therebracket support 90. The quenching fiuid is supplied to thetubular rod by means of a flexible hose connection 91 at the lower endof the tube.- Exhaust quenching fluid is drawn off from theexhaustchamber through the outlet conduit 00 and pressure valve 99 and a trapor gas and liquid separator I00 for separating such of the inert gas asmay pass downwardly into the exhaust chamber 05.

Operation of the pneumatic motor cylinder 50 is controlled through anelectro-magnetically' operatedcontrol valve IOI and piston valve I02operable in known manner upon energization to exhaust the top of thecylinder 50 and admit air to the bottom thereof to raise the piston 52to the top of the cylinder and upon deenergization to exhaust the lowerend of the cylinder and admit air to the upper end to effect downwardmovement of the piston thus operating upon energization to raise thetransformer shell 5| into the position shown and upon deenergization toeffect lowering of the transformer shell to move the primary winding 63out of cooperative relation with the secondary winding 04 and intocooperative relation with the low reluctance magnetic circuit element0|.

To insure operation of the various parts in proper sequence for carryingout a complete drum of insulating material has formed thereon or in-settherein various commutator sectors such as S, L, etc. for effectingelectrical contact with stationary contact brush elements S, L, etc.respectively during rotation of the drum and in proper sequence. Toeffect proper timing of the sequence of circuit closure by thecontroller, the drum I03 is arranged to be rotated at a predeterminedrate by means of a suitable driving motor Ill, preferably a synchronousmotor and IiII after retract the quenching head back to its lowermostposition shown-in Fig. 9 0i the drawings. I

Movement of the quenching head is properly coordinated with the movementof the heating coil I0 to follow the upward movement of the heating coilthrough the gun barrel in constant spaced relation to the coil asdetermined by. In the present embodiment this coordinated movement ofthe quenching head. is effected by means of a driving motor SI operatingthrough a pinion l2 through suitable reduction gears I05. Current forthe control system may be derived from any suitable source of currentsupply here indicated as an ordinary commercial line I06. which for thesake of simplicity in circuit connections is shown as having the lowerside earthed or grounded as indicated by a ground symbol'E and the upperside free or ungrounded, such connections as lead from the apparatus tothe grounded side of the line being indicated by a similar groundconnection symbol. As indicated in the circuit diagram. the controlcommutator drum I03 is provided with a starting signal control segment Spermanently connected to the free sid of the line through conductor I01while all of he other segments L. HD. G. etc. are connected to the freeside of the line through normally open contact I00 of a locking relayI09 by ative to effect connection of the free side of the line to theirassociated brushes L, HD', G, etc.

only during closure of the contact I08 of locking relay I09. 7

For control of the traversing motors 41 and9I for raising and loweringthe heating coil I and quenching nozzle 81, respectively, the motors I'Iand 9I are provided with pole-changer switches H2, H3 respectivelysuitably arranged for eflecting the proper changeof polarityforreversing their respective motors in any suitable manner according tothe type of motor. As the two motor circuit diagrams are alike, it willbe necessary to describe but one of them, for example, that of theheating coil traversing motor 41 which it will be noted comprises thepole-changer switch H2 heretofore mentioned arranged to be normally heldin an open circuit position as by the centering retractile springs Illconnected to the pivoted arms II of the switch below the pivotal points,the pivoted arms of the switch being arranged to be moved to one side orthe other by solenoids or magnets H6, H1, respectively, to energize themotor for rotation in one or the other direction for bringing about adownward or upward movement of the heating coil I0. Similarly,

the pole-changer switch H3 is moved to the right or left by magnets H0and H9, respectively, for movement of the quenching head 01 downwardlyand upwardly. The control of pressure fluid to the motor cylinder 50 iseffected by an electromagnetic valve IOI, control of the inert gassupply to the pressure control valve 02 is efiected through anelectro-magnetic valve I and control of the quenching fluid from asuitable source of supply to the flexible hose connection 41 leading tothe quench-head 01 is effected by an electro-magnetic valve I2I. Oneterminal of each of the operating magnets IIG, etc. and theelectro-magnetic valves IIII, etc.', is connected to the grounded sideofthe line I06 as diagrammatically shown while the ungrounded terminalsof each of such operating magnets and electromagnetic valves arearranged to be connected to the free side of the line I06 atpredetermined intervals through their respective control brushes andcommutator segments on the controller I03. The controller also governsthe connection of the primary winding 56 of the switching transformer toa source I22 of high frequency current through an electro-magneticallyoperated line switch I23 whose operating magnet like the various otheroperating magnets has one terminal normally grounded and the otherterminal arranged to be connected with the free side of the line I06through a brush and commutator segment of the controller. A startingsegment I24 and starting push button I25 complete the control equipment.

In operation. assuming that a gun to be operated upon is in position inthe machine as shown in the several drawings, the upper terminal chamber10 in place on the muzzle of the gun I0 in sealed relation thereto, theheating coil element I0 in the raised position and wholly within theupper terminal chamber, the quench-head 01 in the lowermost position asshown in the several views, and the various circuits and apparatuselements of the control system in the position indicated in the diagramFig. 12 with the controller drum I03 rotating to move the variouscommutators S, L, etct, in the direction indicated by arrow adjacent tothe drum, continued rotation of g the drum from the position shown firstbrings the commutator segment S, normally connected to the free side ofthe line through conductor IIII, into contact with its associated brushS thus connecting the free side of the line to the ungrounded terminalof the starting signal lamp I24 which lights the lamp indicating to theoperator that the controller is ready to start its cycle of operations.The operator may then start the cycle of operations by pressing thestarting button I25 which completes the energizing circuit of thelocking relay I09 over a path which may be traced from the grounded sideof'line I06 .through locking relay I09, push button I25, controllerbrush S, segment S, conductor I0'I to the free side of line I06.gization attracts its armatures connecting the free side of line I06through conductor III and j normally open contact I08 (now closed) toconductor IIO through which the connection from 'the free side of lineis extended to all of the controller segments L, HD, etc., excepting thestarting segment S as indicated by the dotted line extension ofconductor IIO through the controller drum. The locking controllersegment L having made contact with its associated brush L at orimmediately after connection of the starting segment S with itsassociated brush, the energization of the locking relay I09 completesits locking circuit through this locking segment over a path which maybe traced from the grounded side of line I06 through relay I09,lockingcontact I26, circuit controller segment L, conductor IIO to free side ofline as previously traced through contact I00 of the locking relay. Thelocking relay I09 thus remains energized maintaining all of thecontroller segments connected to the free side of line during thepassage of the long locking segment L under its associated brush L.

The controller segment I-ID now engaging its associated brush HD'completes a circuit from ductors I21 to-cause operation of the motor 4'!in a direction to move the heating coil I0 downwardly from the upperterminal chamber 18 through the bore of the gun and into the lowerterminal chamber II as indicated in Fig. 9 of the drawings. Immediately.after the heating coil I0 starts its downward movement the controllersegment G starts engagement with its associated brushG through which itefiects connection of the free side of line I06 to electro-magneticvalve I20 to energize the same and connect the pressure control valve 62to a suitable source of supply of dry inert gas.. The upper terminalchamber I8 as the heating coil leaves the chamber, following the coildown and continuing to fill and maintain the bore of the gun filledunder suitable pressure during the downward movement of the heating coiland con-'- tinuing after the heating coil reaches its lowermostposition, the gas escaping through the clearance between the heatingcoil and the sides of the lower terminal chamber and out through thevent conduit 83. .The length of the heating coil control segment lationto the speed of the controller and the rate of downward movement of theheating coll I0 as to pass beyond the brush. HD' immediately Lockingrelay I09 upon ener-* dry inert gas thus enters the.

HD is so proportioned in re- I heating coil to come to after the heatingcoil reaches the bottom of the lower terminal chamber 1 I. Any known orother suitable means may be provided for causing the the free side ofline I06 with the operating magnet of the electromagnetic line switchI23 which thereupon connects the primary winding 56 of the switchingtransformer with the source of high frequency current I22. However, theheating coil 10 is not energized at this point because of the fact that,as shown in the diagram in Fig.

rest in the lower position 13, the primary winding 50 is uncoupled fromthe secondary winding 63. Soon after this point in the cycle thecommutator segments QV and ST for controlling the supply of quenchingfluid and for actuating the switching transformers, respectively, passinto engagement with their respective.associated-brushes Q11 and ST. Thecommutator segment QV efiects connection of the free side of line I06through commutator segment QV' to the electromagnetic control valve I2Iwhich, becoming energized, connects the quench-head 01 through flexiblehose connection 91 to a suitable source of supply of,quenching fluidunder pressure. The commutator segment ST connects the free side of lineI06 through its complementary brush ST to the electromagnetic valve I0lwhich energizing admits air to the lower end of motor cylinder 50raising the transformer shell and with it the primary transformerwinding 56 of the switching transformer into a transformer couplingrelation with the seconda y winding 62. The heating coil 10 is nowenergized from the secondary winding 62 over the hollow conductors 13.With the heating coil thus energized and the quenching head operating tospray qunenching fluid outwardly in the space surrounding the quenchinghead below the heating coil, the commutator segments HU and QU move intocontact with their respective brush elements HU' and QU' to connect thefree side of line I06 with the operating magnets H1 and H9 of thepole-changer switches H2 and Hi to connect the 'motor 41 and 9| throughthe branch circuits I21 and I28 respectively to the line circuit I06 ina manner to cause the motors to rotate in a direction to move both theheating coil 10 and the quenching head 81 upwardly through the barrel ofthe gun, the quenching head 81 following the heating coil upwardlythrough the barrel until the heating coil enters and comes to rest inthe upper terminal chamber 18, at which time the segments HU and QU passfrom under their respective brushes to'deenergize the control magnets H1and H9 which in turn permit restoration of the pole-changer switches tothe intermediate or open circuit position thus eilecting deenergizationof their respective motors 41 and 9|. The operation of the motors 41 and9I is so timed that the heating coil will move upwardly through the boreof the gun, at the constant rate required to effect the proper heatingfollowed by the quenching head 91, the quenching head' following alwaysin abutment against the lower end ofthe heating coil 10 through thespacing piston diaphragm 88 to insure constant spaced relation betweenthe zone heated and the point of application of quenching fluid. Theparts may be coordinated in any suitable as by accurate timing of themotors or, preferably, by having the motor 9I,'of a constant torquetype, designed to.overcome the weight of the spray head and its movableparts with suflicient margin of power to urge the quenching head up 2wardly always in contact with the bottom of the heating coil 10.

After the heating coil enters the uppermost ter- I minal chamber 10, thecommutator segments HI) and QU moving out of contact with theirrespective. brushes EU and QU' open the circuit of the magnets H1 and H9to deenergize the motors l1 and 9|. Movement of the heating coil all theway upinto the upper terminel chamber followed all the way by thequenching head both stopping in their extreriie upper positions withoutundue .strain on the machinery may be-assured in any known or othersuitable manner as suggested in connection with the stopping of theheating coil in its lowermost position within the lower.

terminalchamber 1 I. Upon entrance of the heating coil into the upperterminal chamber, the segment G of the controller passes .out from underits associated brush G breaking connection between the free side of lineI06 and the brush G. This deenergizes electromagnetic valve I20 cuttingoff the supply of gas to the regulating valve 82. Substantially at thesame time,'the switching transformer control segment ST passes out ofcontact with its associated brush ST' disconnecting the free side'of'line I06 from this.

brush thus deenergizing electromagnetic valve 1 0| which operates toexhaust pressure fluid from the bottom of the motor cylinder and'admitpressure fluid to the top thereof to move the casing of the switchingtransformer downwardly and with it the primary winding '50 restoring theswitching transformer to its uncoupled position. Movement of theswitching transformer to uncoupled position brings the primary winding56 into inductive relation with the low reluctance magnetic circuitfurnished by the laminated core extension 6| to prevent unfavorablechange in the reactance of the circuit of the switching transformer.

After uncoupling of the switching transformer 56, the control segment LSmoves out of contact with its associated brush LS disconnecting the freeside of line I06 from the latter and thereby deenergizing theelectromagnetic line switch I23 and disconnecting the primary coil 56from the source I22 of high frequency current. The commutator segment QVnow passing out of contact with brush QV opens the circuit of theelectromagnetic control valve I2I which deenergizing cuts of! the supplyof quenching fluid from the quenching head 91. Control segment QD nowmoves into contact with its associated brush element QD', connecting thefree side of line I06 to said brush and thereby completing theenergizing circuit of operating magnet I I9 of pole-changer switch "H3which magnet upon energization moves theswitch -I I3 to the left toconnect the motor 9| through extension conductors I26 to the line I06for reverse movement to effect down- -ward movement of the spray head 61to the lowermost position as indicated in Fig. 9 of the drawings. whenthe spray head 61 reaches such lowermost position,

manner to insure this following of the coil by the quench-head thesegment QD moves out cult of magnet II8 which permits the polechangerswitch I I3 to move into open circuitposition, deenergizing motor 9|.The length of the segment QD is so proportioned in relation to the speedof the motor BI and the speed of the controller I03 as to effect thisdeenergization of the motor when the quenching head 81 reaches itslowermost position. Any known or other suitable means, not shown, may beprovided to enable the quenching head 81 to come to rest in the positionshown in Fig. 9 of the drawings without undiie shock to the mechanismand without imposing undue load on the motor 9|, such for example as theuse of a slipping clutch connection or resilient lost-motion connectionbetween the quench-head tube 86 and the driving motor or by suitableselection of the electrical characteristics of the motor. After thesegment QD passes from under its brush QD, the locking circuit segment Lpasses from under its associated brush L' opening the locking circuit ofrelay I09 previously maintained through this segment and the lockingcontact I26. The initial energizing circ'uit of relay I09 being open atthe push button I25, the relay becomes deenergized opening theconnection between conductor H0 and the free side of line I06 at contactI08 thus removing the -line connections from all of the commutatorsegments except the starting-signal segment S.

The controller thus restored to normal with the various apparatus andcircuit elements in the position as shown in Fig. 12 leaves theapparatus in a position with the heating coil III in the upper pressurechamber 18 clear of the muzzle of the gun, and the quenching head 81 inthe lowermost position, as shown in Fig. 9 of the drawings outside andclear of the breech of the gun. The gun thus heat-treated is now free tobe removed'from the machine after release from the various clamping andholding elements such as the arms 20 and 21 and the centering clamp II.

o A gun so treated is shown in Fig. 12 of the drawings where theheat-treated portion near and including the inner surface of the bore isin dicated at I29 During upward movement of the heating coil 10 closelyfollowed by the quenching head 81, quenching fluid is kept out ofcontact with the coil or the clearance space between the coil and thebore of the gun by means of the separating piston member 88, leakage ofquenching fluid beyond the piston through the slight clearance betweenthe piston and the walls of the gun bore being prevented by the presenceof the inert gas under pressure in the spaces above the quenching headand by the downward passage of such gas through the clearance between.the separating piston 88 and the walls'of the gun bore. Any gas passingout through the quenching fluid outlet conduit 48 (where a liquidquenching fluid is used). may be separated 01f from the liquid by theliquid trap IOI (Fig. 1).

Inasmuch as the heating coil I0 is initially energized for its upwardmovement through the barrel of the gun before entering the breech of thegun and is maintained energized after leaving the muzzle to insure aneven treatment of the gun barrel throughout its length, it is desirableto maintain the electrical characteristics of the heatingcoilsubstantially constant during such movement and during its completetime of energization. This is to insure that the energy outi put-of thecoil will remain substantially constant throughout its passagethroughthe gun barrel 22,064 of contact with the brush QD; opening the cirandduring its energization while outside of the gun barrel in either theupper or lower terminal chambers, and it is for this purpose that thelow reluctance laminated inner wall or linings 15 and 15 are providedfor the upper and lower terminal chambers 18 and II, respectively.Prefer-' ably such low reluctance elements are arranged to maintain theinductive reaction of the heating coil Ill substantially constantthroughout its travel from the lower terminal chamber to the upperterminal chamber, or otherwise affect such reactance to preventundesirable change in power factor dueto removal of the coil from thesurrounding low reluctance material of the gun.

While I have herein shown and described a preferred embodiment of myinvention for the sake of disclosure, it is to be understood that theinvention is not limited to the specific embodiment shown and described,but contemplates all such variants and modifications thereof as fallfairly within the scope of the appended claims.

What I claim is:

1. An apparatus of the type described comprising means for holding anobject having a cylindrical bore, an induction heating element arrangedto be moved into and out of the bore of the object held by said holdingmeans, a quenching nozzle arranged to follow said heating element intothe bore near the trailing end of the heating element, and means formaintaining an inert gas inthe bore on the side of the heating elementremote from the quenching nozzle and in the clearance between theheating element and the bore. 7 I

'2. An apparatus of the type described comprising means for holding anobject having a cylindrical bore, an induction heating element arrangedto be moved into and out of the bore of the object held by said holdingmeans, a quenching nozzle arranged to follow said heating elementintoqthe bore near the trailing end of the clearance between saidheating element and said nozzle in a direction from the heating elementtoward the nozzle.

3. Apparatus for heat-treating elongated hollow cylindrical objects ofmagnetic material at and near the inner surface comprising anelectromagnetic induction heating element less in length than the lengthof the inner surface to be treated and provided with an internal coreonly, and arranged to have its magnetic circuit completed substantiallywholly .by the material of said object, means for moving the heatingelement from a point outside the object into and through the hollow ofthe object to a point outside /the object, and low reluctance meansarranged at each end of the object to form a substantially continuousextension of the object and to contain the entire portion of the heatingelement not contained in the workpiece object during the entire entranceand withdrawal movement of the heating element.

4. Apparatus for heat-treating elongated hollow cylindrical objects ofmagnetic material at and near the inner surface comprising anelectromagnetic induction heating element less in length than the lengthof the'inner surface to be treated and provided with an internal coreonly and arranged to have its magnetic circuit completed substantiallywholly by the material of the said object, means for moving the heatingelement from a point outside the object into and through the hollow ofthe object to a point outinto and out of opposite ends side the object,and low reluctance means arranged ateach endof the. object formaintainingthe inductive. reactance of said heating element during theentire entrance and withdrawal movement .of the-latter. into and fromthe hollow obiect at leastsubstantially equal to the inductive reactanceofsaid heating element during its presence in the hollow object;

. 5..Apparatus for heat-treating elongated hollow cylindrical objects ofmagnetic material at ing element partly or .wholly out of the object tomaintain substantially the full inductive load of the heating element.

-6. Apparatus for heat-treating elongated hollow cylindrical objects ofmagnetic material at and near the inner surface, comprising means forholding the object. .to be treated, an electromagnetic induction heatingelement adapted to be passed through the hollow of the object, areceptacle at each end of the object arranged to receive the. heatingelement during its passage of the object, means for guiding the heatingelement through the object from one of said receptacles to the other,means for moving said heating element in said guided path, saidreceptacles being formed in part of magnetic material and sealed incommunication with the interior of the object to provide with theinterior of the object a substantially gas tight enclosure, switchingmeans controlling the'flow of current to said heating element, gascontrol means controlling the supply of gas to the interior of saidobject and said receptacles, and control means for controlling theoperation of said heating element moving means, said gas control meansand said switching means in predetermined timed order.

- '1. Apparatus for heat treating a hollow cylinthe heating element 9.Apparatus for heat treating an object having a cylindrical bore,comprising an induction heating element arranged to be moved through thebore of the object, a closure cover for one end of the bore, a boreclosurev piston element arranged to follow the heater element in itsmovement through the bore toward the closure cover,

and means for maintaining an inert gas within the bore between saidcover and the heating element and surrounding the heating element. i

10. Apparatus for heat-treating elongated hollow cylindrical objects ofmagnetic .material at and near the inner surface, comprising means forholding the object to be. treated, an electromagnetic induction heatingelement adapted to be passed through the hollow of the object, areceptacle at one end of the object arranged to receive. the heatingelement during its passage into and out of the object, means for guidingthe heating element through the object from one end to the other, meansfor moving said heating element in said guide path, said receptaclebeing formed in part of magnetic material and substantially sealed incommunication with the in-' terior of the object to provide with theinterior of the object, a gas retaining enclosure, switching meanscontrolling the flow of current to said heating element, and gas controlmeans controlling the supply of gas to the interior of said object andsaid receptacle.

11. Apparatus for heat treating, at and near the inner surface;elongated hollow cylindrical objects of magnetic material having acontinuous circular cross section, comprising an electromagneticinduction heating element less in length than the length of the objectto be treated, and provided with a core arranged to lie internally ofthe object and to have its magnetic circuit completed substantiallywholly by the material of said objects, means for moving the heatingelement through the hollow of the object to a point outside the object,and means composed of magnetic material arranged at one end of theobject I .to form a substantially continuous extension of drical objecthaving axially contiguous inner cylindrical surfaces, comprising anelectromagnetic induction heating element arranged to be placed withinthe object adjacent said contiguous surfaces, and an annular element oflaminated; low reluctance material arranged to be placedwithin theobject in 'telescoping relation between one of said surfaces and anaxial por tion only of said heating element for shielding the one ofsaid surfaces from the inductive heating of said heating. element andfor providing in series with the other axially contiguous cylindricalsurface of the object a magnetic circuit for said heating element.

8. Apparatus for heat treating the bore of an elongated hollowcylindrical object having an axial end portion of its bore enlarged indiameter,

. comprising an induction heating element less in length than the lengthof the. bore to be treated,

means for moving said heating element axially within the bore of theobject for generating heat in different-portions thereof, and'alaminated low reluctance element of annular cross-section arranged toform a substantially continuous axial extension of the one end of theobject, and extending into the axial portion of enlarged diameter tolessen the heating eil'ect of the heating coil upon said axial portion.

, the object of continuous annular cross section,

into which the entire heating element may pass during the withdrawalmovement of the latter.

12. Apparatus for heat treating elongated hollow cylindrical objects ofmagnetic material at and near the inner surface, comprising an elec-'tromagnetic induction heating element less in length than the length ofthe object to be treated. and provided with a core arranged to lieinternally of the object and to have its magnetic circuit completedsubstantially wholly by the material of said object, means for movingthe heating element through the hollow of the object to a point outsidethe object, and means composed of magnetic material arranged at one endof the object to form'with the object and the aforesaid coresubstantially the entire magnetic circuit of the induction heatingelement.

13. Apparatus for'heat treating hollow cylindrical metallic objects atand near the inner surdrical objects of magnetic material at and nearthe inner suriace comprising an electromagnetic inductionheatingvelement less in length than the length of the object to betreated, and provided with a core arranged to lie internally of theobject and to have its m netic circuit completed substantially wholly{by the material of said object, means for moving the heating elementthrough and outside of the object, and means composed of magneticmaterial of continuous annular cross section arranged to form asubstantially continuous object.

t 15. Apparatus for heat treating a surface portion of an elongatedobject, comprising anelectromagnetic induction heating element, meansfor moving the heating element along the object in the direction ofelongation of the object and beyond one end of the object and meanscomposed of magnetic material arranged to form a longitudinal extensionof the object from the end beyond which the heating element is moved andhaving a transverse cross section of substantially the same shape asthat of the said end portion of the object whereby uniform heattreatment may be effected along the object and at the end thereof. Y t

' 16. Apparatus for heat treating a surface portion of an elongatedobject, comprising an electromagnetic induction heating element, meansfor quenching, means for moving the heating element and the quenchingmeans along the ob- J'ect in the direction of elongation of the objectin fixed spaced relation and beyond one end of the object andmeanscomposed of magnetic material arranged to form a longitudinal extensionof the object from the end beyond which the heating element is moved andhaving atransverse cross section of substantially the same shape as thatof the said end portion of the ob ject whereby uniform heat treatmentmay be effected along the object and at the end thereof.

17. Apparatus for heat treating a surface portion of an elongatedobject, comprising an .electromagnetic induction heating element, meansaxial extension of the l ing element adapted to induce said surfacecur-' rents for a distance along the object less than the lengththereof, means for quenching and means for moving the heating elementand the quenching means along the length of the object in fixed spacedrelation between an intermediate point between the ends of the objectand a point beyond one end of the object, a magnetic means of lowreluctance material having a transverse cross section of substantiallythe same shape as that of the object arranged at the end of the objectand adapted to form a longitudinal extension of the object, wherebysubstantially uniform heat treatment from the said intermediate forquenching, means for moving the heating element along the object in thedirection of elongation of the object and beyond one end of the objectand means for moving the quenching element with said heating element infixed spaced relation, and means composed of magnetic material arrangedto form a longitudinal extension,

of the object from the end beyond which the heating element is moved andhaving a trans-.

element adapted to induce said surface currents for a distance along theobject less than the I length thereof, means for moving the heatingelement along the length of the object between an intermediate pointbetween the ends of the object and a point beyond one end of the object.

a magnetic means of low reluctance material having a transverse crosssection of substantially the same shape as that of the object arrangedat the end of the object and adapted to formia longitudinal extension ofthe object, whereby substantially uniform heat treatment from the saidintermediate point to the end point of the object may be eflected.

point to the end point of the object may be effected,

20. In combination an induction heat-treating head having an'inducingcoil of definite axial length arranged to be passed through a hollowcylindrical workpiece from outside of one end through and out of theother end, a holder for the wdrkpiece, and a pair of annular end piecesof low magnetic reluctance carried by the holder arranged to form shorthollow cylindrical extensions for each end of the workpiece effectivelyextending each end adistance equal to at least the entire axial lengthof the said coil.

21. In combination, an induction heat-treating head having an inducingcoil of definite axial length arranged to be passed through at least aportion of a hollow cylindrical workpiece adjacent to and including anend thereof and for a short distance outside of the end, a holder forthe workpiece and an annular end of low magnetic reluctance carried bythe holder arranged to form a short hollow cylindrical extension for the7 end of the workpiece, effectively extending the end a distance equalto at least the entire axial length of the coil.

22. In combination, an inductive heating coil arranged to move into andout of inductive relation with a workpiece, and a magnetic circuitelement of low reluctance, means for holding said circuit element andthe workpiece in endto-end relation during the entire heat treatingoperation of the end of the workpiece, said heating coil being arrangedto move into operative relation with said magnetic circuit element uponmovement out of inductive relation with the workpiece to effect uniformheat treatment of the end of the workpiece during said movement.

23. In combination, an inductive heat-treating head having an inducingcoil of definite-axial length arranged to inductively heat treat asurface of a metallic object to be heat treatedat least adjacent an endthereof, a core element coaxial with said coil, and means of lowmagnetic reluctance adapted to be associated adjacent the said end ofthe object in end extension relation therewith to provide, upondisposition of said coil adjacent the said end of the object ininductive heating reiaion with the said surface thereof, a lowreluctance magnetic circuit for said coil consisting in series said coreelement, the adjacent axial extent of the object and the said endextension, whereby uniform heat-treatment of the said surface at thesaid end may be effected.

HOWARD nsouns.

